Safety paper



Patented May 3, 1927.

, R'UJELGEES W. fiMKTH, F ROCHESTER, NEW YORK, ASSIGNOR T0 THEE TQDJD @QMEANY,

ILWGQRPORATED, 0F ROCHESTER, NEW YORK, A QORPORATEQN 0i? NEW "YQRK.

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This invention relates to safety or fraud prcvcntntivc paper for use, for cxmmplc, for making checks, drafts, bonds ond other popcr instruments, and morc 'porticulorly 5 to tho variety of such paper hoving s chomicol ,ingrcdicnt incorporotcd thcrcin for rcoction with ink erodicoting substances in such or manner os to indicate and warn of ottcmptcd oltorations, tho chict object of tho invention being to provide on cfiicicnt paper of this notnre cdcpted to ho economicslty manufactured in s Wide variety of stylcs ond coiors," ond to bc ooickl end shnrpiy chongcd or. deepened in color by the npplicntion of on ini: crcdicotor to oilford o conspicuous, snhstnntioily perms nent worming off ottcmpts to slter mctter written thercon. I

\"To these ond othcr cnds tho invention rosidcs in ccrtoin improvc'mcnts ond combi= notions of ports, all of which vviil be here insider snore fully described, the novel features being pointed out in the claims at y the end of the specificotion,

Sofcty papers hovs been mods with chomicci substances incorporated in them for rccction with ink er'adicotors' to indicate attemptsat oltcration'by the development of it change in color, Such papers, howcvcr, 301love enerolly been open to the objection that ile chemicals employed have 1n one way or another been unsatisfactory, either because insuflficiently sensitive in reaction with eradicotors, or because the products of such reaction have been relatively soluble or reducible to colorless compounds and on able of removal from the pa r, or for ot or reasons. It has been foun that these difliculties are overcome with marked sucy 40 cess through the incorporation in the paper.

\ of certain or anic substances found to possess the various qualifications essential to the production of a commercially ractical and efiicient safety paper. These su stances I belong to a related group. or family charactorized by the presence of naphthalene or anthracene rings, and their essential characteristics are believed to be due to the presence of a molecular confi uration or arrangement comprising a napht alone or anthracene radical or analo ous roup of rings having a. carbon atom irect y joined to a carbon atom of another carbon ring or cup of rings and havin a. lurality of ammo radicals substituted %or ldydrogen atoms. Among have ,firmly held to the paper. The have been found suitable for the Application no! o s 13%, mos. sens no. misc.

This is so solid reacting with oxidising l ogcnts, such as sodium hypcchlorits, yield crimson or purplish precipitates as high degree of color value and insolnbility, The various isomers of this compound, such as dinsphthyline, have thssome choroctcrist-ics, but as for as invcstigoted hovc not the desired characteristics to the some on tcnt. For example, their solts ore rclstivcly soluble, While the basic substances have the same characteristics dcscribsd shove,

- It is believed that this configuration need not .be symmetrical, but that the groups may vary in the number of carbon rings and in the disposition of the amino radicals. For example, the compound may be composed of a radical or group known as the anthracene rin coupled tothe on known as a na fiithalene ring, and t e disposition of the amino radicals may be in various positions thereof.

It is preferred to use the solts'las, for example, the sulphates or chlorides, as they eater stability than the base under the in uence of moisture and light rays and because the reactionprecipitates are more sulphates; purposes of this invention. It is probable however that there are other com ounds having the essential characteristics diascribed ab0ve,as well as their salts, which may be used with substantially the some success.

The above substances are afl'ected little when subjected to atmospheric conditions or strong light for an indefinite period and, in

addition to this advantageous feature, they are highly sensitive to the usual ink era'dicating chemicals such as potassium dichromate, potassium permanganate, hypochlorite, and other oxidizing substances in reaction with which they afford precipitates which are conspicuously deep in color as well as relatively insoluble and from which the color is not discharged by the usual re ducing agents. When an eradicating chemical is applied to safety paper containing one of these substances, the latter reacts quickly and sharply to develop a conspicuous color over the area treated and the relatively insoluble stain thus produced affords a conspicuous warning of an attempt at erasure. A further advantage of the substances described lies in the fact that they are practically colorless and may thereforebe employed to produce white safety paper, or may be readily employed with paper having a desired tint orcolor, while of course any known and suitable coloring matter may be added to these compounds as may be desired.

In the incorporation of a sensitive compound of the class described the quantity to be employed varies of course with the depth of stain desired upon reaction, the rate of absorption by the paper, the apparatus used and other factors understood in the art. It has been found that for a ton of pulp when added in the beater or j ordan, thirty pounds is sufiicient of a substance of the above character which I believe tobe alpha-naphthidine sulphate and which I prepare by the oxidation of alpha-naphthy amine in sulphuric acid with ferric oxide, as described by F. Reverdin and G. De La Harpe in the Chem.-Ziet. 16, 1687. The resultant of this reaction is believed to be al ha-naphthidine sulphate, somewhat contaminated with the various isomers and incidental byproducts; nevertheless the material prepared as described is well suited for the purpose outlined without completely isolating the base where it is desired to use the sulphate.

The chemical ingredients described may be added to the paper after the latter. is formed by passing the web through baths or by incorporating it in the sizing itself. Furthermore, the low relative solubility of some of the salts admits of their production in the web itself by double decomposition. For example, sue insoluble salts may 1 readily be formed by impregnation of the paper. with a soluble salt of the base, and then by passing the web through an acid or salt of an acid such as sulphuric acid or sulphate of soda, which will by double decomposition produce the desired insoluble salt, or the base may be dissolved and the salt formed by acids in the same manner. A chemical ingredient oi the class described thus has an additional advantage of being comprisin 2. A safety paper having incorporated.

therewith an organic compound having a molecular arrangement comprising a group of carbon rings joined together by having two carbon atoms in each ring in common with the adjacent ring, a carbon atom of said group of rings being attached to a carbon atom of another group of carbon rings similarly bound together and a plurality of amino radicals substituted in said rings for hydrogen atoms, said compound being deepened in color by reaction with ink eradicating chemicals.

3..A safety paper having incorporated therewith a salt of a basic organic compound having a molecular arrangement comprisin a group of carbon rings joined together gy having two carbon atoms in each ring in common with the adjacent ring, a carbon atom of said grou of rings being attached to a carbon atom 0 another carbon ring, and a plurality of amino radicals substituted in said rings for hydrogen atoms, said compound being deepened in color by reaction with ink eradicating chemicals.

4. A safety paper having incorporated therewith a salt of a basic organic com,- pound having a molecular arrangement a group of carbon rings joined together y having two carbon atoms in each ring in common with the adjacent ring, a carbon atom of said group of rings being attachedto a carbon atom of another group of carbon rings similarly bound together and a plurality of amino radicals substituted in said rings for hydrogen atoms, said compound being deepened in color by-reaction with ink eradicating chemicals.

5. A safety paper having incorporated therewith an organic compound having a molecular arrangement comprisin of carbon rings joined together y having two carbon atoms in one ring of. the groop in common with an adjacent ring, a carbon atom of said group of rings other than one of said common carbon atoms being linked to a carbon atom of another carbon ri and a plurality of amino radicals substituted in said rings for hydrogen atoms, said a group .tion with ink compound being deepened in color by reaceradicating chemicals.

6. A safety paper having incorporated therewith a compound of the aromatic series having carbon rings with two carbon atoms in common and also having carbon rings with carbon atoms and'a plurality of amino radicals substituted in saidrings for hydrogen atoms, said compound being deepened in color by reaction with ink eradicating chemicals.

7. A safety paper having incorporated therewith an or anic compound having a plurality of car 11 rings comprising two types of ring connections, one being by means of two carbon atoms in common, the other being the chainv type of connection, and a plurality of amino radicals substituted in said rings for hydrogen atoms, said linked together,

8. A safety paper having incorporated therewith an organic compound having a, molecular arrangement characteristic of alpha-naphthidine and its salts.

9. A safety aper having incorporated therewith a su phate of an'orgaiuc compound .whose molecular arrangement comprises a group of carbon rings joined together by havlng two carbon atoms in each rin in common with the-adjacent ring, a car on atom of said group of rings being attached to a carbon atom of another carbon ring and a plurality of amino radicals substituted 'in said rings for two hydrogen atoms, said paper being reaction with chemical ink eradicators. 10. A safety paper having alpha-naphthldine incorporated in the body or sizlng thereof.

compound being deepened in color by .reaction with ink eradicating chemicals.

'- BURGESS w. smm' deepened in color by 

